An Object Is Dropped from Rest into a Pit,and Accelerates

Multiple Choice

An object is dropped from rest into a pit,and accelerates due to gravity at roughly 10 m/s2.It hits the ground in 5 seconds.A rock is then dropped from rest into a second pit,and hits the ground in 10 seconds.How much deeper is the second pit,compared to the first pit? Neglect air resistance.

A) four times deeper
B) two times deeper
C) three times deeper
D) five times deeper